Area Forecast Discussion
Issued by NWS Kansas City/Pleasant Hill, MO

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FXUS63 KEAX 191653
AFDEAX

AREA FORECAST DISCUSSION
National Weather Service Kansas City/Pleasant Hill MO
1153 AM CDT Wed Jul 19 2017

.Discussion...
Issued at 324 AM CDT WED JUL 19 2017

An area of isentropic accent over the KS/MO border has helped to
develop elevated convection and mid level cloud coverage over this
region. This will also be the first sign that WAA is on its way for
the area. These storms are not expected to last long after sunrise
as they will lose their forcing once the LLJ starts to weaken
over eastern Kansas. Although the storms will dissipate the mid
level cloud coverage may stick around through the early morning
into the late afternoon. With this added cloud coverage the high
temperatures have been lowered a degree or two especially over
north central Missouri where the clouds will persist the longest.
These clouds shouldn`t have to much effect on the KS/MO border as
this will be the first area to clear out. Even with a slight
decrease in temperatures high temps are expected to reach into the
mid 90s and upper 90s over the metro area with heat index values
ranging from 103-110F. The highest heat index values will be north
of the Missouri River and closer to the Nebraska border.

The upper level ridge will slowly start to shift to the east
Thursday allowing lower level thermal ridge to become entrenched
over northern Missouri through Saturday.  The 850mb temperatures
will go from 21C Wednesday to 25C on Saturday.  Mixing is expected
to occur up to and even higher than this level so Friday and
Saturday will be the hottest day for most of the area with 100
degrees possible over the urban areas with heat index values between
105-110F. As the ridge weakens over the central plains it will allow
a shortwave push through the great lakes area setting up a backdoor
cold front over Iowa Saturday.  The southern extent of this boundary
will have significant effects on the high temperatures Saturday with
the current thinking that it will stay far enough north that the
excessive heat will still occur Saturday afternoon along the IA/MO
border.  There is some uncertainty to weather this boundary will
help form some convection along the warm sector as the ECMWF has a
line of storms over central MO, but GFS remains dry. Looking at
ECMWF skew T data it doesn`t show convective temperature being
reached or enough lifting to create convection so this precip signal
seems suspect and PoPs remain only slight chance for now.

This frontal boundary will finally start to push south Sunday
morning increasing precipitation chances into the early afternoon
and dropping temperatures into the upper 80s to lower 90s which
finally drops our heat index below 100F. The colder air and lower
dewpoints will make Monday the nicest day this area has had in quite
a while with highs in the mid 80s and little to no heat index
difference.  The cold front that shifted south into southern
Missouri will return as a warm frontal boundary Tuesday afternoon
which will be the precursor to another warmer than average pattern
going into the middle of next week.

&&

.Aviation...(For the 18Z TAFS through 18Z Thursday Afternoon)
Issued at 1146 AM CDT WED JUL 19 2017

VFR through the period. Cloud debris from earlier precipitation will
thin and exit the area over the next few hours. No additional
convection is expected to impact terminals over the next 24 hours.
Surface wind speeds should remain high enough to limit LLWS concerns
overnight.

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
KS...Excessive Heat Warning until 8 PM CDT Saturday for KSZ025-057-
     060-102>105.

MO...Excessive Heat Warning until 8 PM CDT Saturday for MOZ001>008-
     011>017-020>025-028>033-037>040-043>046-053-054.

&&

$$

Discussion...Barham
Aviation...Blair


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